Patent GB-1301113-A (GB)
Title: Device for the error-correcting transmission of data
IPC: G11C7/10
Filed: 1969-12-15
Abstract: 1301113 Data transmission systems; changing speed of transmission TELEFUNKEN PATENTVERWERTUNGS GmbH 15 Dec 1969 [14 Dec 1968] 61019/69 Heading H4P A store having a plurality of storage cells is used as a buffer to accommodate the difference in the speed between reception and transmission. The store, which may be a core matrix, is arranged for non destructive readout and is controlled so that when a data source works more slowly than a transmitter the storage is first substantially filled before transmission is began and further writing is continued but when the source has a higher speed than the transmitter, transmission is began immediately on reception. In the event of an error a control device repeats the readout. A source of data 1 e.g. a punched tape is connected through a parallel to serial converter 1<SP>1</SP> and a ferrite core store 2 to a transmitter 3. The store may have for example 64 rows and 16 columns, the counter 5 selecting columns and counter 6 selecting rows. Before transmission a control device 13 sets all counters to zero except a counter 12 which is set at minus 3. When source 1 works faster than transmitter 3 the first bit is deposited in column 1 row 1 directed by counters 7, 8 and the second bit in row 2, &c. When column 1 is filled counter 7, which counts modulo 16, is stepped 1 by device 13 and the second counter 8 which counts modulo 64 is reset to 1. Previous information is overwritten and in this mode the first bit is read out as soon as possible after it has been stored. Read out, which at this stage should be non-destructive, is controlled by counters 5, 6 in a similar manner and the data may be transmitted together with check bits. Since the store works faster than the transmitter, interlaced co-operation between source 1 and store 2 also store 2 and transmitter 3 is controlled by device 13. If reception is correct a acknowledgement signal is passed through a receiver 10 to a counter 11 the count in which should correspond with that in store 2. If the reception is an error the signal is passed through device 13 which stops the transmission and transfers the count in 11 to counter 5 which causes a renewed read out. If an error again occurs the control device transfers the count in counter 12, which is 3 less than that in counter 11, into counter 5 which enables data blocks already reported as correct to be transmitted again. When the source works more slowly than the transmitter, store 2 is filled as far as possible, then transmission begun and further writing is performed simultaneously. When store is empty data reception takes place. Regions of store 2 requiring possible repetition which should not be overwritten is ensured by device 13 comparing the counts of 7, 8 with the count in 12 and arresting writing unless there are 3 blocks between writing and read out. Data received at 14 from a remote transmitter may be passed into temporary store 15 which together with further write counters 16, 17 and read counters 18, 19 are connected to device 13. For temporary storage, store 2 is possibly divided so that some columns are controlled by counters 5-8 and others by counters 16-19. Storage and read out are interlaced by device 13. Retransmission is not possible when the rate of reception is faster than store 15 is able to receive it.